/*
 *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_
#define MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_

#include <array>

#include "array_view.h"
#include "ns_common.h"
#include "quantile_noise_estimator.h"
#include "suppression_params.h"

namespace webrtc {

// Class for estimating the spectral characteristics of the noise in an incoming
// signal.
    class NoiseEstimator {
    public:
        explicit NoiseEstimator(const SuppressionParams &suppression_params);

        // Prepare the estimator for analysis of a new frame.
        void PrepareAnalysis();

        // Performs the first step of the estimator update.
        void PreUpdate(int32_t num_analyzed_frames,
                       rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum,
                       float signal_spectral_sum);

        // Performs the second step of the estimator update.
        void PostUpdate(
                rtc::ArrayView<const float> speech_probability,
                rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum);

        // Returns the noise spectral estimate.
        rtc::ArrayView<const float, kFftSizeBy2Plus1> get_noise_spectrum() const {
            return noise_spectrum_;
        }

        // Returns the noise from the previous frame.
        rtc::ArrayView<const float, kFftSizeBy2Plus1> get_prev_noise_spectrum()
        const {
            return prev_noise_spectrum_;
        }

        // Returns a noise spectral estimate based on white and pink noise parameters.
        rtc::ArrayView<const float, kFftSizeBy2Plus1> get_parametric_noise_spectrum()
        const {
            return parametric_noise_spectrum_;
        }

        rtc::ArrayView<const float, kFftSizeBy2Plus1>
        get_conservative_noise_spectrum() const {
            return conservative_noise_spectrum_;
        }

    private:
        const SuppressionParams &suppression_params_;
        float white_noise_level_ = 0.f;
        float pink_noise_numerator_ = 0.f;
        float pink_noise_exp_ = 0.f;
        std::array<float, kFftSizeBy2Plus1> prev_noise_spectrum_{};
        std::array<float, kFftSizeBy2Plus1> conservative_noise_spectrum_{};
        std::array<float, kFftSizeBy2Plus1> parametric_noise_spectrum_{};
        std::array<float, kFftSizeBy2Plus1> noise_spectrum_{};
        QuantileNoiseEstimator quantile_noise_estimator_;
    };

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_
